The present invention relates to clocks, and in particular to a radio controllable clock.
Radio controlled clocks are capable of automatically adjusting the time after successfully receiving a radio time signal and decoding the signal to drive the hand shafts of an associated analog clock to an exact time position. To accurately set the time of the analog clock, the second hand shaft, minute hand shaft, hour hand shaft and optionally the alarm hand shaft each have to start at a datum/reference position whenever the system is reset, so the microcontroller knows the starting position and can calculate how many pulses must be generated to rotate each shaft to the desired position.
Conventional reset mechanisms are relatively complicated, especially in cases where photoelectric barriers are used and the respective rays have to pass through holes provided in respective gears of the hand shafts. In addition, photoelectric barriers are susceptible to malfunctions and in the event of such a malfunction, it is impossible to reset the radio controlled clock.
Therefore, there is a need for a radio controllable clock that facilitates reliablely setting the time displayed by an analog clock.